Sometimes, when a USB 3.0 device is disconnected, the Intel Panther Point xHCI host controller will report a link state change with the state set to "SS.Inactive". This causes the xHCI host controller to issue a warm port reset, which doesn't finish before the USB core times out while waiting for it to complete. When the warm port reset does complete, and the xHC gives back a port status change event, the xHCI driver kicks khubd. However, it fails to set the bit indicating there is a change event for that port because the logic in xhci-hub.c doesn't check for the warm port reset bit. After that, the warm port status change bit is never cleared by the USB core, and the xHC stops reporting port status change bits. (The xHCI spec says it shouldn't report more port events until all change bits are cleared.) This means any port changes when a new device is connected will never be reported, and the port will seem "dead" until the xHCI driver is unloaded and reloaded, or the computer is rebooted. Fix this by making the xHCI driver set the port change bit when a warm port reset change bit is set. A better solution would be to make the USB core handle warm port reset in differently, merging the current code with the standard port reset code that does an incremental backoff on the timeout, and tries to complete the port reset two more times before giving up. That more complicated fix will be merged next window, and this fix will be backported to stable. This should be backported to kernels as old as 3.0, since that was the first kernel with commit a11496ebf37534177d67222285e8debed7a39788 "xHCI: warm reset support". Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxx --- drivers/usb/host/xhci-hub.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index 1e96d1f..723f823 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -761,7 +761,7 @@ int xhci_hub_status_data(struct usb_hcd *hcd, char *buf) memset(buf, 0, retval); status = 0; - mask = PORT_CSC | PORT_PEC | PORT_OCC | PORT_PLC; + mask = PORT_CSC | PORT_PEC | PORT_OCC | PORT_PLC | PORT_WRC; spin_lock_irqsave(&xhci->lock, flags); /* For each port, did anything change? If so, set that bit in buf. */ -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
